The correct answer is option 1, red phosphorus. Red phosphorus is the type of phosphorus used in the manufacture of safety matches.

Option 2, black phosphorus, is a different allotrope of phosphorus that is used in various applications, but not in the production of safety matches.

Option 3, white phosphorus, is another allotrope of phosphorus that is highly reactive and toxic. It is not used in safety matches due to its volatile nature.

Option 4, scarlet phosphorus, is not a recognized allotrope of phosphorus and is not used in any industrial applications.

To summarize, red phosphorus is preferred for safety matches because it is stable and less toxic compared to white phosphorus, and does not possess the same volatility or high reactivity as other forms of phosphorus such as black or scarlet phosphorus.